Fermionic Spectral Functions in a Two-Current Gubser-Rocha Model with Axion Momentum Relaxation

We investigate fermionic spectral functions in a two-current Gubser-Rocha background with linear-axion momentum relaxation. Serving as a comparison channel, the dipole coupling $p_1$ is found to produce a soft asymmetric reconstruction without opening a clean hard Mott gap. Our main analysis then focuses on two axion-dependent non-minimal couplings modulated by current mixing. The $p_2$ tensor channel suppresses the zero-energy Fermi peak and shifts the dominant spectral weight to finite frequencies, resulting in a flat-bottom reconstruction. In contrast, the $p_3$ vector channel creates a strong spectral asymmetry in momentum space, generating open, Fermi-arc-like segments. Varying the momentum-relaxation strength $β/μ$ and the doping parameter $χ$ reveals a channel-dependent response to the two-current background. Increasing $β/μ$ generally broadens the $p_2$ response, whereas the one-sided $p_3$ feature varies non-monotonically under changes of the background parameters. These results clarify how current mixing, axion-induced momentum relaxation, and non-minimal fermion couplings jointly reshape holographic fermionic excitations. These results clarify how current mixing, axion-induced momentum relaxation, and non-minimal fermion couplings jointly reshape holographic fermionic excitations.

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Authors

Cai-E Liu; Defu Hou

Published

Oct 8, 2026

Paper type

preprint

Source

Arxiv